This invention relates generally to knob control devices, and more particularly to control knob devices including force feedback and additional input functionality.
Control knobs are used for a variety of different functions on many different types of devices. Often, rotary control knobs offer a degree of control to a user that is not matched in other forms of control devices, such as button or switch controls. For example, many users prefer to use a rotary control knob to adjust the volume of audio output from a stereo or other sound output device, since the knob allows both fine and coarse adjustment of volume with relative ease, especially compared to button controls. Both rotary and linear (slider) knobs are used on a variety of other types of devices, such as kitchen and other home appliances, video editing/playback devices, remote controls, television, etc.
Some control knobs have been provided with xe2x80x9cforce feedback.xe2x80x9d Force feedback devices can provide physical sensations to the user manipulating the knob. Typically, a motor is coupled to the knob and is connected to a controller such as a microprocessor. The microprocessor receives sensor signals from the knob and sends appropriate force feedback control signals to the motor so that the motor provides forces on the knob. In this manner, a variety of programmable feel sensations can be output on the knob, such as detents, spring forces, or the like.
One problem occurring in control knobs of the prior art is that the knobs are limited to basic rotary motion. This limits the control options of the user to a simple, one-degree-of-freedom device that does not allow a variety of selection options. In addition, if force feedback is provided on the knob, the limited control functionality of the knob limits the user from fully taking advantage of the force feedback to provide more control over desired functions.
The present invention provides a knob control interface that allows a user to control functions of a device in a variety of ways. Embodiments of the knob controller include additional degrees of freedom for the knob and force feedback applied to the knob.
More particularly, in one embodiment a knob controller device of the present invention includes a knob coupled to a grounded surface. The knob is rotatable in a rotary degree of freedom about an axis extending through the knob, and the knob also moveable in a transverse direction approximately perpendicular to the axis. A rotational sensor detects a position of the knob in the rotary degree of freedom, and a transverse sensor detects a position of the knob in the transverse direction. An actuator is coupled to the knob to output a force in the rotary degree of freedom about the axis, thus providing force feedback. In a preferred embodiment, the knob is moveable in multiple transverse directions. For example, the transverse sensor includes a switch that detects when the knob is moved in a transverse direction; the switch can be a hat switch having multiple individual switches, for example. In one embodiment, the knob is moveable in four transverse directions spaced approximately orthogonal to each other.
Furthermore, a local microprocessor can be includes to control the force feedback on the knob. The microprocessor receives sensor signals from the rotary and transverse sensors and controls a function of a device in response to the sensor signals. The device can be any of a variety of electrical or electronic types of devices. The device can also include a display, wherein an image on said display is changed in response to manipulation of the knob in the transverse direction. A method of the present invention for controlling functions of a device from input provided by a knob similarly uses sensor signals from a rotary sensor and a transverse sensor to control at least one function of a device, such as adjusting a frequency of a radio tuner or updating a displayed image based on at least one of the sensor signals.
In another aspect of the present invention, a knob is coupled to a grounded surface, where the knob is rotatable in a rotary degree of freedom about an axis extending through the knob. The knob is also moveable in a linear degree of freedom approximately parallel to the axis. A rotational sensor and a linear sensor detect positions of the knob in the respective degrees of freedom. An actuator is also coupled to the knob and operative to output a force in the rotary degree of freedom about the axis, thereby providing force feedback to the knob. The linear degree of freedom of the knob allows it to be pushed and/or pulled by the user, where the push or pull motion is detected by the linear sensor. A spring member is preferably included for biasing the knob to a center position in the linear degree of freedom. The linear sensor can, for example, include a grounded switch that is contacted by a pusher member coupled to the knob when the knob is moved in the linear degree of freedom. Alternatively, the linear sensor can detect a position of the knob within a detectable continuous range of motion of the knob. The transverse degree of freedom of the previous embodiment of the knob can also be included. A microprocessor preferably receives the sensor signals and controls a function of a device in response to the sensor signals, and also sends force feedback signals to the actuator to control forces output by the actuator.
In a different aspect of the present invention, a method for providing detent forces for a force feedback control includes outputting a first force by an actuator on a user manipulatable object, such as a rotary knob, for a first detent when the user object is moved within a range of the first detent. The first force assists movement of the user object toward an origin position of the first detent and resists movement away from the origin position. A second force for a second detent is also output on the user object when the user object is moved within a range of the second detent, similar to the first force. A portion of the range of the first detent overlaps a portion of the range of the second detent. The overlapped portions of the ranges preferably modifies the second force such that a force at the beginning point of the second detent range has less magnitude than a force at an endpoint of the second detent range. Preferably, the first force and second force each have a magnitude that increases the further that the user object is positioned from that detent""s origin. Preferably, the direction of the knob changes the range endpoint magnitudes such that if the knob is moved in the opposite direction, the first-encountered point of the first detent range has a lesser magnitude than the last-encountered point.
In another aspect of the present invention, a method for providing detent forces for a force feedback control includes defining a periodic wave and using at least a portion of the periodic wave to define a detent force curve. The detent force curve defines a force to be output on a user manipulatable object, such as a rotary knob, based on a position of the user manipulatable object in a degree of freedom. The detent force curve is then used to command the force on the user manipulatable object as output by an actuator. The type, period and magnitude can be specified for the periodic wave. The detent force curve can be defined by specifying a portion of said periodic wave to be the width of the detent force curve, specifying a phase and an offset to be applied to said periodic wave to define the detent force curve, and/or specifying an increment distance between successive detents.
The apparatus and method of the present invention provide an control knob for a device that includes greater control functionality for the user. The linear and transverse degrees of freedom of the knob allow the user to select functions, settings, modes, or options with much greater ease and without having to take his or her hand off the knob. Force feedback may also be added to the knob to provide the user with greater control and to inform the user of options and selections through the sense of touch. Force feedback detent implementations of the present invention provide overlapping detent ranges to allow more accurate control of a knob by a user within closely-spaced detents, and an efficient, convenient method for defining detents from periodic waves.